Air slides

ABSTRACT

An air slide for imparting both lift and direction to a semiconductor wafer, the air slide comprising a guide plane having a plurality of arcuate recesses in the surface thereof, the recesses having side and bottom walls with the bottom wall of each of the recesses having an upward slope which merges into the surface of the guide plane substantially in the direction of intended motion of the semiconductor wafer. In the embodiment shown, a longitudinally extending plenum chamber may be connected so as to underlie the track or be positioned at opposite lateral edges of the track, the edge connection of the plenum chambers enhancing the ability for close spacing and thus tiering of the guide planes. Additionally, disclosed are two basic track structures which permit of alternate air supply sources, such as a fan or high pressure air.

United States Patent Yakubowski [54] AIR SLIDES [72] Inventor: CarlYakubowski, Poughkeepsie,

[73] Assignee: International Business Machines Corporation, Armonk, NY.

'22] Filed: March 29, 1971 21] App1.No.: 128,777 I ment De c. 19, 197 2Prin zary Examiner-Harvey C. Hornsby Assistant ExaminerH. S. LaneAttorney-Hanifin & Jancin and William .1. Dick [57] ABSTRACT An airslide for imparting both lift and direction to a semiconductor wafer,the air slide comprisinga guide plane having a plurality of arcuaterecesses in the-surface thereof, the recesses having side and bottomwalls with the bottom wall of each of the recesses having an upwardslope which merges into the surface of the guide plane substantially inthe direction of intended motion of the semiconductor wafer. 1n theembodishown, a longitudinally extending plenum chamber may be connectedso as to underlie the track or be positioned at opposite lateral edgesof the track, the edge connection of the plenum chambers enhancing theability for close spacing and thus tiering of the guide planes.Additionally, disclosed are two basic track'structu'res which permit ofalternate air supply sources, such as a fan or high pressure air.

14 Claims, 7 Drawing Figures PATENTEME: 19 I972 3' 706 475 sum 1 or 2 F3 INVENTOR CARL YAKUBOWSKI mi/wym ATTORNEY AIR SLIDES SUMMARY OF THEINVENTION AND STATE OF THE PRIOR ART upwardly sloped bottom walls topermit air to egress 0 with both a lift and direction component.

In the transport of semiconductor wafers, i.e. thin slices of silicon,it is desirable to eliminate, or at least reduce, human contact with thewafer wherever possible to prevent contamination or injury to thesurface of the wafer. Conventional air lift and directional movementequipment is hampered by a high cost per foot and because of the volumeof air requirements and/or pressure requirement require expensiveauxiliary air supply equipment regardless of the length of trackrequired. Additionally, existing state of the art slides conventionallyrequire large bulky plenum chambers which creates. problems in tieringthe slides for multidirectional transport, especially where closespacing requirements are demanded.

In view of the above it is a principal object of the present inventionto provide a novel air slide for imparting both lift and direction to aworkpiece placed thereon.

Another object of the present invention is to provide an air slide whichis adaptable for both long and short runs to permit the supply of airthereto to be accomplished by existing in house air supply systems or asimple fan.

Yet another object of the present invention is to provide an air slidewhich may be easily tiered so as to permit simultaneous sending andreceiving of workpieces in which the limitation of tier spacing is theheight of I the object.

Still another object of the present invention is to provide an air slidewhich is simple in operation and manufacture and which may be fabricatedfrom inexpensive materials.

Other objects and a fuller understanding of the invention may be had byreferring to the following specification and claims taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a fragmentary schematic plan view of an air slide constructedin accordance with the present invention;

FIG. 2 is an enlarged fragmentary perspective view of a portion of theair slide shown in FIG. 1;

FIG. 3 is an enlarged fragmentary plan view of another embodiment of anair slide constructed in accordance with the present invention;

FIG. 4 is a fragmentary sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a fragmentary perspective view of another embodiment of theair slide of the present invention;

FIG. 6 is a fragmentary side elevational view of a portion of the slideshown in FIG. 5; and

FIG. 7 is a plan view of another embodiment of the air slide of thepresent invention being used as a tumtable transport.

Referring now to the drawings, and particularly FIG. 1 thereof, an airslide or track 10 particularly adapted for imparting lift and directionto a workpiece, in the illustrated instance a semiconductor wafer 11, isillustrated therein. The air slide or track, in the embodimentillustrated in FIGS. 1 and 2 includes a guide plane 12 bounded onopposite longitudinal edges, in the present instance with low upstandingwalls 13 and 14 which serve to prevent the workpiece or wafer 11 frombeing laterally discharged off of the slide.

In accordance with the invention, means are provided in the guide plane12 for imparting lift to the workpiece while propelling the same (whenprovided with a suitable flow of gaseous media) along the directionshown by the arrows 15 in FIG 1. To this end,

a plurality of arcuate narrow recesses 16, each having closely spacedupstanding side walls 17 and an upwardly sloped bottom wall joining theside wall 18, is

provided. In the illustrated instance, and for reasons which will becomeevident hereinafter, the bottom wall 18 of each of the recesses mergesinto the guide plane at a'point so as to cause air to flow substantiallyin the direction of intended motion of the workpiece.

In order to permit entry of a gaseous media into the arcuate recesses, aplenum chamber is connected to the recesses to thereby permit a flow ofair along the recesses in a direction substantially along the axis ofthe recess, i.e. up the sloped bottom wall 18. To this end, the airslide or track 10, in the embodiment illustrated in FIG. 2, includes alongitudinally extending channel 19 which serves as the plenum chamberfor the air slide. In the illustrated instance the channel 19 bisectsthe arcuate recesses forming a clear passage for air or other gaseousmedia to enter into the plenum chamber as by inlet means 20. The lowerportion of the channel 19 may be closed as by a support plate 21 or thechannel may be formed directly in the material of the track 10.

In order to cause the air entering the inlet means to flow in adirection substantially along the axis of the arcuate recesses, covermeans 22 close off the upper surface of the channel 19 forming the uppersurface of the plenum chamber. In the illustrated instance (FIG. 2) thecover means includes a longitudinally extending strip 23 which isfittable into a ledge-shaped recess 24 cut into the side walls 19A and19B of the channel 19. In this manner the air inlet openings from theplenum chamber into the recess form an orifice 16A defined by I theunderside of the strip 23, and the side and bottom walls 17 and 18respectively of the recesses 16.Thus the cover means 22 serves as abaffle to cause air to flow from the plenum chamber into the airrecesses in a direction substantially along the axis of the recesses.

In the embodiment illustrated in FIGS. 1 and 2 a simple muffin fan maybe connected to the inlet means 20 and effect sufficient air flow tocause the workpieces to be lifted above the surface or guide plate 12while imparting direction to the workpiece. For example, using a Rotronmuffin fan with approximately C.F.M. at zero (0) static pressure,approximately 10 feet of track may be serviced. With ten (10) feet oftrack length the static pressure restricts the fan output to roughlytwenty (20) C.F.M. Of course multiple fans may be utilized spaced alongthe track at appropriate intervals depending upon, of course, the cubicfeet per minute rating of the fan, the size of the recesses and ofcourse the orifice 16A.

In the event that it is desired'to utilize the air track of the presentinvention for long runs while utilizing the in-house plant air system, amore efficient air flow or reduced air flow is required.

To this end the embodiment illustrated in FIGS. 3 and 4 may be employed.Referring now to those figures, a guide plane 30 includes a pluralityofarcuate recesses 31, each having upstanding side walls 32 and 33 andupwardly sloped bottom walls 34. The bottom wall of each of the arcuaterecesses merges into the guide plane at a point so as to cause air toflow substantially in the direction of intended motion of the workpiece.The nature of the recess is in effect the same as that disclosed inFIGS. 1-2 and above described. In

order to permit entry of a gaseous media such as air into the arcuaterecesses 31 a plenum chamber 35 is formed in a similar manner asdescribed hereinbefore. A longitudinally extending recess 36 is providedin the guide plane 30 and adapted for receiving cover means 37 identicalto the cover means 22 described relative to FIGS. 1 and 2. However,thedepth of the arcuate recesses in such that the recesses do notintersect the plenum chamber 35. Accordingly, an aperture or orifice 38may be formed through the arcuate recess into the plenum chambersubstantially along the center line of the recess 36 thus providingfluid communication between the plenum chamber 35 and therecesses 31.The small orifices 38 then he in a plane substantially perpendicular tothe guide plane such that when the cover means 37 is in position, air isdirected along the axis of the arcuate recesses causing the air flow toegress in a forward and upward direction out of the guide plane 30.

As the apertures or orifices 38 may be relatively small, the volume ofair flow is reduced but of necessity the air pressure interiorally ofthe plenum chamber must be increased due to the increase in resistance.Thus with an air slide of this construction, a low pressure in-house airsupply may be used.

The structure of the present invention permits the tiering of the airslides so that a multiplicity-of workpieces may be transportedsimultaneously in the same or opposite directions. To this end and asbest illustrated in FIGS. and 6, a plurality of guide planes 40, 50 and60 are shown in superimposed juxtaposition relation, in the illustratedinstance each of the guide planes being connected to a plenum chamber70, 71 disposed along the opposite longitudinally extending edges 41,42, 51, 52, 61, 62 of the guide planes.

The arcuate recesses 43, 53, 63 formed in the surface of each of theguide planes 40, 50 and 60 each have upwardly sloped bottom walls whichmerge into the surface of the respective guide planes so as to impartboth lift and direction to workpieces such as wafers 11 in the directionof intended motion (see arrows 40A, 50A). As illustrated the recesses ineach of the planes is formed in. left and right hand sets, for example,the left hand set 43A in guide plane 40 being connected to .plenumchamber 70 through suitable orifice-like apervery close intervals.Additionally, the recesses may be formed in opposite directions, suchthat the wafer 11A supported above guide plane 40 is caused to betransported from left to right, while the wafer 113 which is supportedabove guide plane 50 intermediate guide plane 40 and 50 is caused to betransported in the opposite direction.

In certain instances where it is desirable to inspect workpieces orobjects as they move by a variety of work stations, an inexpensive airslide constructed in accordance with the present invention may beutilized in lieu of a turntable. For example, the air slide may beconstructed in the form of a circular track having a plurality ofarcuate recesses 81 similar to that heretofor described. In that eventthe workpiece 82 may be transported in a circular fashion about thetrack by placing the workpiece 82 on the slide and transported from onestation to any other station disposed about the perimeter of the trackwithout rotationthereof. .Of course means, in the present instance anupstanding annular wall 83, must be provided to prevent centrifugalforce from ejecting the workpiece radially outward from the track.

The slide of the present invention may be constructed of any convenientmaterial such as nylon, Delrin (trademark of DuPont de Nemours) etc. therecesses being formed either by molding, or even angulating a circularhole saw.

Thus the present invention provides a novel air slide for imparting bothlift and direction to a workpiece, the air slide being readily adaptedfor both long and short runs to permit the supply of air theretoto beaccomplished by existing in-house air supply systems or a simple fanarrangement. Additionally, the present invention is easily adapted topermit simultaneous sending and receiving of workpieces at or by tieringthe slides thereby effecting spatial economies.

Although the invention has been described with a certain degree ofparticularity, it is understood that the present disclosure has beenmade only by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may be madewithout departing from the spirit and the scope of the invention ashereinafter claimed.

What is claimed is:

1. An air slide for imparting lift and direction to a workpiece placedthereon; said air slide comprising: a track including a guide planehaving a plurality of narrow elongated arcuate recesses in the surfacethereof, each of said recesses having closely spaced side walls and abottom wall joining said side walls, said bottom wall being slopedupwardly and merging into said guide plane substantially inthe'direction of intended motion of said workpiece, a longitudinallyextending plenum chamber connected to said track, and means connectingsaid plenum chamber to said recesses, and means to cause air to flowfrom said plenum chamber into said arcuate recesses in a directionsubstantially along the axis of said recesses.

2. An air slide in accordance with claim 1 wherein said plenum chamberunderlies said track.

3. An air slide in accordance with claim 2 including a longitudinallyextending recess in the upper surface of said air slide, a channelunderlying said recess and extending longitudinally along said track,said channel being in fluid communication with said arcuate recesses.

4. An air slide in accordance with claim 3 wherein said channel extendsfrom said longitudinally extending recess and forms part of said plenumchamber.

5. An air slide in accordance with claim 3 including a bottom wall insaid longitudinally extending recess, and a plurality of apertures insaid bottom wall extending through said bottom wall and providing saidmeans for fluid communication between said plenum chamber and saidlongitudinally extending recess.

6. An air slide in accordance with claim 3 including cover meansoverlying said longitudinally extending recess.

-7. An air slide in accordance with claim 1 wherein said plenum chamberis disposed along at least one longitudinal edge of said guide plane.

8. An air slide in accordance with claim 7 including a second plenumchamber disposed along the opposite longitudinally extending edge ofsaid guide plane.

9. An air slide in accordance with claim 7 including a plurality ofguide planes in superimposed juxtapositioned relation, each of saidguide planes being connected to said plenum chamber.

10. An air slide in accordance with claim 8 wherein said arcuaterecesses are arranged in a set, one of said set being coupled to one ofsaid plenum chambers and the other of said set being coupled to theother of said plenum chambers.

11. An air slide in accordance with claim 10 including a plurality ofguide planes in superimposed juxtapositioned relation, each of saidguide planes being connected to each of said plenum chambers and havingrecesses arranged in sets.

12. An air slide in accordance with claim 1 1 wherein said set ofrecesses in one of said guide planes is disposed to impart direction toa workpiece opposite to the direction of a second workpiece supported byanother of said guide planes.

13. An air slide in accordance with claim 1 wherein said track iscircular in shape, forming a turntable.

14. An air slide in accordance with 13 including wall means along theperiphery of said track.

1. An air slide for imparting lift and direction to a workpiece placedthereon; said air slide comprising: a track including a guide planehaving a plurality of narrow elongated arcuate recesses in the surfacethereof, each of said recesses having closely spaced side walls and abottom wall joining said side walls, said bottom wall being slopedupwardly and merging into said guide plane substantially in thedirection of intended motion of said workpiece, a longitudinallyextending plenum chamber connected to said track, and means connectingsaid plenum chamber to said recesses, and means to cause air to flowfrom said plenum chamber into said arcuate recesses in a directionsubstantially along the axis of said recesses.
 2. An air slide inaccordance with claim 1 wherein said plenum chamber underlies saidtrack.
 3. An air slide in accordance with claim 2 including alongitudinally extending recess in the upper surface of said air slide,a channel underlying said recess and extending longitudinally along saidtrack, said channel being in fluid communication with said arcuaterecesses.
 4. An air slide in accordance with claim 3 wherein saidchannel extends from said longitudinally extending recess and forms partof said plenum chamber.
 5. An air slide in accordance with claim 3including a bottom wall in said longitudinally extending recess, and aplurality of apertures in said bottom wall extending through said bottomwall and providing said means for fluid communication between saidplenum chamber and said longitudinally extending recess.
 6. An air slidein accordance with claim 3 including cover means overlying saidlongitudinally extending recess.
 7. An air slide in accordance withclaim 1 wherein said plenum chamber is disposed along at least onelongitudinal edge of said guide plane.
 8. An air slide in accordancewith claim 7 including a second plenum chamber disposed along theopposite longitudinally extending edge of said guide plane.
 9. An airslide in accordance with claim 7 including a plurality of guide planesin superimposed juxtapositioned relation, each of said guide planesbeing connected to said plenum chamber.
 10. An air slide in accordancewith claim 8 wherein said arcuate recesses are arranged in a set, one ofsaid set being coupled to one of said plenum chambers and the other ofsaid set being coupled to the other of said plenum chambers.
 11. An airslide in accordance with claim 10 including a pluralIty of guide planesin superimposed juxtapositioned relation, each of said guide planesbeing connected to each of said plenum chambers and having recessesarranged in sets.
 12. An air slide in accordance with claim 11 whereinsaid set of recesses in one of said guide planes is disposed to impartdirection to a workpiece opposite to the direction of a second workpiecesupported by another of said guide planes.
 13. An air slide inaccordance with claim 1 wherein said track is circular in shape, forminga turntable.
 14. An air slide in accordance with 13 including wall meansalong the periphery of said track.